This is a good question. What doesn't look good for Pete is his record against some of Fed's main rivals.
For example:
27-30 year old Sampras was only 4-5 vs a 17-21 year old Hewitt. 2 of Hewitt's losses were when he was a teenager and was ranked outside the top 40. Once Hewitt was ranked in the top 20, he was 5-2 vs Sampras. And it wasn't as though Sampras was THAT old. Sampras was 30 when he played his last match against Hewitt.
Also, Safin was 4-3 vs Sampras. One of Sampras' wins was when the 60th ranked Safin was only 17 years old.
And lastly, Sampras was 1-2 vs Roddick. And Roddick had just turned 20 the last time that he faced Pete. Andy was ranked outside the top 10 each time they faced off.
I watched Safin and Hewitt absolutely destroy Sampras in the US Open final. Tennis at that time seemed to hit new heights. That is, until Federer figured the game out.
And of course, Federer would later play over 80 matches against Djokovic and Nadal, two players that are upgraded versions of Hewitt.
With that being said, I'd say that Federer faced slightly tougher competition. However, his competition was nowhere near as tough as the 1980's.